Robotic device for providing vertical mobility

ABSTRACT

A robotic device for providing vertical mobility has a payload is disposed inside a central compartment and supported by a skid. The skid can move up and down through latch and hook pairs to keep intimate contact with the surface and cross over bumps. The apparatus uses a flexible seal to create a reliable vacuum chamber. The flexible seal comprises a foam ring inside fabric pocket. A plurality of rod and spring strips are configured to apply a downward force to the flexible seal to conform with surface curvatures. The fabric pocket fills in the gaps or seams to maintain a vacuum. The air flows inside a manifold and passes through a filter to avoid debris from damaging the vacuum motor assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a non-provisional of U.S.Patent Application 62/357,607 (filed Jul. 1, 2016), the entirety ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to robotic devices that moveacross a vertical surface. There are three major challenges in usingvacuum to attach and move across a wall. The first challenge ismaintaining mobility while at the same time sticking strongly to thewall. This first challenge is significant as these properties arecontradictory. The second challenge is maintaining a seal while movingacross the wall. This is difficult as there are many types of surfacessuch as flat surfaces or faces with curvatures as well as surfacefeatures, such as seams or ridges, which may make it difficult tomaintain a vacuum seal. The third challenge is avoiding debris that candamage the impeller or vacuum motors. It is very common for concretestructures to have debris that are likely to damage the device. Animproved device is therefore desirable.

The discussion above is merely provided for general backgroundinformation and is not intended to be used as an aid in determining thescope of the claimed subject matter.

BRIEF DESCRIPTION OF THE INVENTION

An apparatus for providing vertical mobility is described. A vacuumchamber is circumscribed by a flexible seal. A vacuum motor and impellerassembly evacuates the chamber and presses a payload, such as a groundpenetration radar (GPR), against a flat surface (e.g. a wall or ground)or curved surfaces (e.g., surface of wind turbine blade).

A robotic device for providing vertical mobility is disclosed that has apayload is disposed inside a central compartment and supported by askid. The skid can move up and down through latch and hook pairs to keepintimate contact with the surface and cross over bumps. The apparatususes a flexible seal to create a reliable vacuum chamber. The flexibleseal comprises a foam ring inside fabric pocket. A plurality of rod andspring strips are configured to apply a downward force to the flexibleseal to conform with surface curvatures. The fabric pocket fills in thegaps or seams to maintain a vacuum. The air flows inside a manifold andpasses through a filter to avoid debris from damaging the vacuum motorassembly.

In a first embodiment, a robotic device for providing vertical mobilityis provided. The robotic device comprising: a housing enclosing a vacuumchamber that is exposed to an opening on a lower surface of the housing;a flexible seal circumscribing the opening; a plurality of rod andspring strips configured to apply a downward force to the flexible seal;a payload disposed inside a central compartment, the payload beingsupported by a skid that is vertically mobile; a vacuum motor assemblyoperatively connected to the vacuum chamber; a means for moving therobotic device across a surface, the means for moving being at least onewheel or at least one tank tread; wherein actuation of the vacuum motorassembly creates a vacuum in the vacuum chamber that pulls the housingtoward the surface such that the means for moving is pressed against thesurface.

In a second embodiment, a robotic device for providing vertical mobilityis provided. The robotic device comprising: a housing enclosing a vacuumchamber that is exposed to an opening on a lower surface of the housing,the vacuum chamber has a central compartment with a payload disposedtherein; a flexible seal that circumscribes the opening; a vacuum motorassembly operatively connected to the vacuum chamber; a means for movingthe robotic device across a surface, the means for moving being at leastone wheel or at least one tank tread, wherein the means for moving isdirectly connected to the housing such that actuation of the vacuummotor assembly creates a vacuum in the vacuum chamber and pulls thehousing toward the surface such that the means for moving is pressedagainst the surface; wherein the payload is supported by a skid suchthat the payload is vertically mobile, but not laterally mobile, withinthe central compartment.

In a third embodiment, a robotic device for providing vertical mobilityis provided. The robotic device comprising: a housing enclosing a vacuumchamber that is exposed to an opening on a lower surface of the housing;a flexible seal circumscribing the opening; a plurality of rod andspring strips configured to apply a downward force to the flexible seal;a ground penetration radar unit disposed inside a central compartmentthat is within the housing, the ground penetration radar unit beingsupported by a skid that is vertically mobile, wherein the groundpenetration radar unit is supported by a skid such that the groundpenetration radar unit is vertically mobile, but not laterally mobile,within the central compartment; a vacuum motor assembly operativelyconnected to the vacuum chamber; a means for moving the robotic deviceacross a surface, the means for moving being at least one wheel or atleast one tank tread; wherein actuation of the vacuum motor assemblycreates a vacuum in the vacuum chamber that pulls the housing toward thesurface such that the means for moving is pressed against the surface.

This brief description of the invention is intended only to provide abrief overview of subject matter disclosed herein according to one ormore illustrative embodiments, and does not serve as a guide tointerpreting the claims or to define or limit the scope of theinvention, which is defined only by the appended claims. This briefdescription is provided to introduce an illustrative selection ofconcepts in a simplified form that are further described below in thedetailed description. This brief description is not intended to identifykey features or essential features of the claimed subject matter, nor isit intended to be used as an aid in determining the scope of the claimedsubject matter. The claimed subject matter is not limited toimplementations that solve any or all disadvantages noted in thebackground.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features of the invention can beunderstood, a detailed description of the invention may be had byreference to certain embodiments, some of which are illustrated in theaccompanying drawings. It is to be noted, however, that the drawingsillustrate only certain embodiments of this invention and are thereforenot to be considered limiting of its scope, for the scope of theinvention encompasses other equally effective embodiments. The drawingsare not necessarily to scale, emphasis generally being placed uponillustrating the features of certain embodiments of the invention. Inthe drawings, like numerals are used to indicate like parts throughoutthe various views. Thus, for further understanding of the invention,reference can be made to the following detailed description, read inconnection with the drawings in which:

FIG. 1 is a top perspective view of an apparatus for vertical mobility;

FIG. 2 illustrates the apparatus of FIG. 1 with the housing shown inphantom;

FIG. 3 is a top exploded view of the apparatus of FIG. 1;

FIG. 4A is a bottom perspective view of an apparatus for verticalmobility;

FIG. 4B is a top perspective view of an apparatus for vertical mobility;

FIG. 5A is an exploded view of another apparatus for vertical mobility;

FIG. 5B illustrates the housing of the apparatus of FIG. 5A;

FIG. 5C is a cut-off view of the apparatus of FIG. 5A showing the airflow;

FIG. 6A is a bottom perspective view of the apparatus of FIG. 5A showinga vacuum chamber with central compartment;

FIG. 6B is a bottom perspective view of the apparatus of FIG. 5A wherethe central compartment is covered by a skid;

FIG. 7 is an exploded view of another apparatus for vertical mobility;

FIG. 8A is a top perspective view of the apparatus of FIG. 7 with acover removed;

FIG. 8B is a front view of the apparatus of FIG. 7 with the coverattached;

FIG. 8C is a cut-off view of the apparatus of FIG. 7 showing the airflow;

FIG. 8D is a front view of the apparatus of FIG. 7 showing the flexiblefoam seal with multiple sections of rod and spring strips;

FIG. 8E illustrates one rod and spring strip;

FIG. 9A is a bottom perspective view of the apparatus of FIG. 7 where acentral compartment is covered by a skid; and

FIG. 9B is a bottom perspective view of the apparatus of FIG. 7 wherethe skid is removed to show the central compartment.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed in this application is an apparatus that provides verticalmobility for non-destructive testing (NDT) instruments and cameras. Suchan apparatus is useful for the purpose of inspection of large structureswith large flat areas such as, but not limited to, building façades,dams, tunnels, and bridges, or surfaces with a curvature such as windturbine blades. The apparatus is designed to be operable in anyorientation whether it be on the ground, on the wall or on a ceiling,and is designed to overcome small gaps, ledges and other features thatmay be found on these surfaces. The device may be configured for otherpurposes such as surveillance and surface cleaning.

This disclosure also provides a method and apparatus for moving on bothrough and smooth surfaces of vertical walls reliably. The method andapparatus permit carrying a payload that can be fitted into a centralcompartment. Examples of payloads include a ground penetration radar(GPR) antenna or other NDT instrument.

There are several configurations described in this disclosure. Theseconfigurations differ in size to accommodate different models of NDTinstrument. Some of the mechanical features that the configurationsshare are a vacuum motor and impeller assembly, filters and manifoldthat allows air flow inside a housing unit, a flexible seal, a means formoving (e.g. a drive train), and a central compartment within a vacuumchamber where the NDT instrument resides.

Apparatus 100 (FIG. 1, FIG. 2 and FIG. 3) is purposed to carry a largedual frequency model GPR antenna for deep penetration intended for damand tunnel inspection. Apparatus 100 comprises a vacuum motor 104; aflexible seal 106; a means for moving 108 and a housing 110. Injectionmolding with a durable plastic, such as Acrylonitrile Butadiene Styrene(ABS), is appropriate for its construction. The apparatus 100 comprisesa chamber (not shown) with an open side which rests on a verticalsurface such as the side of a building. In one embodiment the flexibleseal 106 is an outer circular flexible seal.

Air is evacuated from the chamber with the vacuum motor 104 to create avacuum inside the chamber which allows the apparatus to adhere to a wallwithout any support from outside. The air passes through a filter (notshown in FIG. 3 but see FIG. 5A) inside the curved duct filtercompartment 101 and is drawn out of the chamber. The chamber does notdirectly contact the wall, but flexible seal 106 are attached and sealedto minimize as much air flow into the chamber as possible. The flexibleseal 106 is comprised of a foam ring wrapped inside a polymer or Nylonfabric pocket and is attached and sealed around the main body to createvacuum chamber and to conform to the contact surface as much aspossible. The square shaped inner flexible skirt seal 103 is attached tothe skirt mount 105 to ensure reliable vacuum and minimize as much airflow into the vacuum chamber as possible. Friction and mobility isprovided by a means for moving 108 such as (1) tank treads or (2) wheelsinstalled on the inside of the chamber on two opposing sides, and thespace in between is left open as central compartment to hold aspecialized payload such as the GPR unit 107. The payload is capable ofcontacting the surface directly for optimized performance. Theaforementioned components are held together by the housing 110 and areprotected by a cover 109. The apparatus is powered by a battery pack111.

The vacuum motor 104 includes an impeller that is designed to drive airout of the chamber and maintain a significant vacuum pressure while atthe same time maintaining a relatively large air flow, as the seal withthe wall is not required to be perfectly air tight. A vacuum motor inthe vacuum motor 104 is provided that matches the torque and rotationsper minute (RPM) required for the impeller is used. A pressure sensor(not shown) can be installed inside the chamber that provides feedbackto rapidly adjust vacuum motor speed in order to maintain low pressureinside the vacuum chamber for maintaining adhesion to the wall at alltimes during operation.

The flexible seal 106 around the perimeter is designed to provide themaximum area for adhesion force, conforming to the surface textures,features and geometry of the wall, while limiting its own force onto thesurface. This is made possible by making the flexible seal 106 slightlylarger than the perimeter of the chamber and making the physicalattachment to the chamber very flexible. One flexible seal design is alow density foam wrapped inside a nylon fabric pocket. The low densityfoam conforms to surface geometry and the nylon fabric fills in gapswhile making the flexible seal relatively air tight. Nylon is abrasionresistant and has a low friction coefficient useful for sliding acrossrough surfaces like concrete. The flexible seal 106 is connected to thechamber by fastening/screwing the pocket rim into the edge of the mainbody with a plastic ring. This way, the majority of the adhesion forcegoes directly to the chamber and therefore the means for moving 108, andonly a small percentage of the down force is exerted onto the flexibleseal 106, thereby allowing the apparatus 100 to move across the surfacewith minimal friction.

The circular shape of apparatus 100 circumscribes the square centerchamber, leaving crescent shaped cavities in the sides, front and back.The sides are populated by the means for moving 108 (e.g., a drivetrain) including the drive motors, wheels and gearboxes. Worm drivemotors are shown used in the design because of their relatively narrowshape and high torque to weight ratio. The front, back and top arepopulated by the vacuum motors and electronics.

The means for moving 108 is made as narrow as possible, in order toallow the GPR instrument to get close to the edge of the walls as muchas possible. The size and power of the drive motors is dictated by theoverall weight of the vehicle. The torque output at the wheels must beable to overcome the weight of the apparatus with its payload because itwill be working directly against gravity as it will typically operate ona vertical surface. Steering is a differential drive for both apparatus100, apparatus 400, apparatus 500 and apparatus 700 allowing for pivotturning.

The payload is often required to contact the wall surface directly forthe best measurement results. Therefore, a cavity with four walls ismade within the chamber to fit around the payload so that it may move upand down, but not laterally. Tolerances are made forgiving to allow fora moderate amount of tilt. The payload instrument is spring loaded ontothe surface with bended spring strips to press the sensor toward thewall surface. The payload's extrusion from the cavity is limited bylatches. See FIG. 7, FIG. 9A and FIG. 9B.

The housing 110 serves multiple purposes as it may be used for noisedampening, and a smooth surface in order to minimize snagging on topower/signal cables and safety cable connecting through the central holeto the device while it moves.

Apparatus 400 (FIG. 4A, FIG. 4B) is designed to carry a different modelof GPR which is approximately six inches across the overall dimensions.Apparatus 400 is much smaller than apparatus 100, as it is intended tocarry a much smaller and lighter GPR instrument, but fundamentally bothdevices are similar.

A square shape of apparatus 400 is used in order to get the GPR as closeto the edges of the wall as possible. Because there is not much space onthe perimeter, the electronics and vacuum motor for this model is placedabove the chamber. Tank treads are used in this design as it servesmultiple purposes: power transmission and friction surface, therebyproviding space savings on the sides.

FIG. 5A depicts another embodiment wherein apparatus 500 is shown.Apparatus 500 comprises a cover 502 and a housing 504. A vacuum motorassembly 506 consists of a vacuum motor 506 a, heat sink 506 b aroundthe vacuum motor 506 a, and an impeller 506 c. The vacuum motor assembly506 draws air from gaps between the contact surface and bottom ofhousing unit and creates a vacuum around a central chamber (600, seeFIG. 6A) that host NDT instrument (e.g., GPR sensor unit) inside acentral compartment. Intake air and/or exhaust air that drawn by thevacuum motor assembly 506 passes through air filters 514 inside thefilter compartment (530, FIG. 5B) to avoid damage of the impeller 506 cby the debris. The air flows within the drive wheel compartment (532,FIG. 5B) and filter compartment 530 along the manifold created by theinner surface of the compartments as shown in FIG. 5 C. An electronicscontrol board 540 and switches 542 are also depicted in FIG. 5B.

In one embodiment, the means for moving 508 comprises a drive motor 534and a drive wheel 536 that are connected by a time belt 538. The drivemotor 534 is operatively connected in the housing 504 and drives thedrive wheel 536 through the time belt 538 and bearings. The drive wheel536 is enclosed inside the drive wheel compartment 532. Anomni-directional wheel 512 facilitates moving of the apparatus 500,including pivot turning. The omni-directional wheel 512 is freely mobileand passive without actuator. The two drive wheels 536 and oneomni-directional wheel 512 are in contact with the wall surface to keepthe housing 504 on planar surface. A payload 516 (e.g. a GPR unit orother NDT sensor) is held within the central compartment 604 by a skid518 within the vacuum chamber 600. The skid 518 attaches to the housing504 with hooks 602 (see FIG. 6A). Four bended spring strips 802 (seeFIG. 6A) on the bottom of the central compartment push the payloadagainst the skid. The hooks have space for the skid (and thus thepayload 516) to move vertically, but not laterally, within the vacuumchamber. Such a configuration helps maintain the payload 516 in closeproximity to the surface while still allowing the payload 516 to moveover bumps.

The housing 504 also comprises a bumper 520 on an external side of thehousing 504 (FIG. 5A). The bumper 520 is operationally connected withhousing 504 to detect obstacles by means of two sets of switches 528 onleft and right sides of housing 504 (FIG. 5B). Each set of switches 528has two switches to detect the bumper motion in two directions(forward/backward, and sideway). Apparatus 500 also has a range sensor522 that scanning in a downward direction to detect edge of a wallsurface. Apparatus 500 comprises a handle 524 that provides a graspinglocation for a gripper to deliver the apparatus to vertical wallsurfaces. Apparatus 500 comprises a visual perception sensor 526 (e.g.,stereo camera) to detect cracks on wall surface, and a servo motor 510that tilts the stereo camera 526 by ±45 degree up and down.

A flexible seal 544 encloses the housing 504 that created the vacuumchamber to adhere to wall surface. As shown in FIG. 5C and FIG. 6A, theflexible seal 544 circumscribes the perimeter of the housing 504, and isprotected by the housing rim 554.

As shown in FIG. 6A, the bottom of apparatus 500 has a flexible seal 554that circumscribes the opening of the vacuum chamber 600 and centralcompartment 604 (see FIG. 6A). FIG. 6B shows the skid 518,omni-direction wheel 512 and the drive wheel 508.

FIG. 7 depicts another apparatus 700 with a housing 704 and a cover 702.A vacuum motor assembly 706 draws air from gaps between the contactsurface and bottom of housing unit and creates a vacuum around a centralcompartment 900, (see FIG. 9B). Intake air and/or exhaust air that drawnby the vacuum motor assembly 706 passes through air filters 714 insidethe filter compartment (FIG. 8C) to avoid damage of the impeller by thedebris. The filter compartment is protected by filter compartment covers728. The air flows within the drive wheel compartment and filtercompartment along the manifold created by the inner surface of thecompartments as shown in FIG. 8 C. A flexible seal 712 is also provided.An electronics control board 720 comprises a microprocessor thatcontrols the operation of the drive motor controller 710, and the vacuummotor assembly 706 through vacuum motor controller 726, via a power andsignal connector 722.

In the embodiment of FIG. 7, the means for moving 708 is a tank treadthat consists of a drive motor 708 a, a time belt 708 b, two wheels 708c that are connected by a tread 708 d and a fastener 708 e. The drivemotor 800 (see FIG. 8A) is operatively connected to the housing 704 byfasteners 708 e and controlled by the drive motor controller 710. Thedrive wheels 708 c and treads 708 d are enclosed inside the drive wheelcompartment. The timing belt 708 b connects to both the drive motor 800and the drive wheel 708 c.

FIG. 8B provides a front view of the apparatus 700, where the flexibleseal 712 circumscribes and overhangs the housing 704.

As shown in FIG. 8D, a flexible seal 712 circumscribes the housing 704and creates a vacuum chamber to adhere to a wall surface. The flexibleseal 712 around the perimeter is designed to provide the maximum areafor adhesion force, conforming to the surface textures, features andgeometry of the wall, while limiting its own force onto the surface.This is made possible by making the physical attachment to the housingvery flexible. One flexible seal design is a low density foam wrappedinside a nylon fabric pocket. Multiple sections of rod and spring stripassembly 802 (see FIG. 8 E) are inserted inside the pocket andcircumscribe the perimeter of the housing unit. Each rod and springstrip assembly 802 comprises a rod 804 and a spring strip 806. Eachsection can push down the foam by the bended spring strip to conform tosurface curvature. The low density foam conforms to surface geometry andthe nylon fabric fills in gaps while making the flexible seal relativelyair tight. Nylon is abrasion resistant and has a low frictioncoefficient useful for sliding across rough surfaces like concrete. Theflexible seal 712 is connected to the chamber by fastening/screwing thepocket rim into the housing edge with a plastic ring. This way, themajority of the adhesion force goes directly to the vacuum chamber andtherefore the means for moving (e.g., drivetrain) 708, and only a smallpercentage of the down force is exerted onto the flexible seal 712,thereby allowing the apparatus 700 to move across the surface withminimal friction.

The central compartment 900 is a cavity with four walls to fit around apayload 716 (e.g. GPR sensors or other NDT instrument) so that it maymove up and down, but not laterally. The payload 716 is held within thecentral compartment 900 by a skid 718. The skid 718 has four latches 724(see FIG. 7 and FIG. 9A) that attach to four hooks 902 on the housing704 (see FIG. 9B). The hook and latch pairs enable the skid to movevertically, but not laterally, within the vacuum chamber. Four rod andspring strip assemblies 802 on the bottom of the central compartmentpush the payload against the skid. The vertical motion of the skidenables the height adjustment for the skid to cross over bumps on wallsurface.

While the invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof to adapt to particular situations without departingfrom the scope of the disclosure. Therefore, it is intended that theclaims not be limited to the particular embodiments disclosed, but thatthe claims will include all embodiments falling within the scope andspirit of the appended claims.

What is claimed is:
 1. A robotic device for providing vertical mobility,the robotic device comprising: a housing enclosing a vacuum chamber thatis exposed to an opening on a lower surface of the housing; a flexibleseal circumscribing the opening; a plurality of rod and spring stripsconfigured to apply a downward force to the flexible seal; a payloaddisposed inside a central compartment, the payload being supported by askid that is vertically mobile; a vacuum motor assembly operativelyconnected to the vacuum chamber; a means for moving the robotic deviceacross a surface, the means for moving being at least one wheel or atleast one tank tread; wherein actuation of the vacuum motor assemblycreates a vacuum in the vacuum chamber that pulls the housing toward thesurface such that the means for moving is pressed against the surface.2. The robotic device as recited in claim 1, wherein the centralcompartment is square.
 3. The robotic device as recited in claim 1,wherein the central compartment is square and comprises a groundpenetration radar unit.
 4. The robotic device as recited in claim 3,wherein the ground penetration radar unit is exposed to the surfacethrough the opening.
 5. The robotic device as recited in claim 1,wherein the flexible seal is larger than a perimeter of the vacuumchamber.
 6. The robotic device as recited in claim 1, wherein theflexible seal defines a seal perimeter and the means for moving isdisposed within the seal perimeter.
 7. The robotic device as recited inclaim 1, wherein the flexible seal is wrapped within a flexible fabricpocket.
 8. The robotic device as recited in claim 1, wherein theflexible seal is wrapped within a flexible nylon fabric pocket.
 9. Therobotic device as recited in claim 1, wherein the vacuum motor assemblycomprises an impeller, the robotic device further comprising a filtercompartment with at least one filter, the vacuum motor assemblyconfigured to pull air through the vacuum chamber and through the atleast one filter before the air passes through the impeller of thevacuum motor assembly, thereby protecting the vacuum motor assembly fromdebris.
 10. A robotic device for providing vertical mobility, therobotic device comprising: a housing enclosing a vacuum chamber that isexposed to an opening on a lower surface of the housing, the vacuumchamber has a central compartment with a payload disposed therein; aflexible seal that circumscribes the opening; a vacuum motor assemblyoperatively connected to the vacuum chamber; a means for moving therobotic device across a surface, the means for moving being at least onewheel or at least one tank tread, wherein the means for moving isdirectly connected to the housing such that actuation of the vacuummotor assembly creates a vacuum in the vacuum chamber and pulls thehousing toward the surface such that the means for moving is pressedagainst the surface; wherein the payload is supported by a skid suchthat the payload is vertically mobile, but not laterally mobile, withinthe central compartment.
 11. The robotic device as recited in claim 10,wherein the payload is a nondestructive testing instrument.
 12. Therobotic device as recited in claim 10, wherein the payload is a groundpenetration radar unit.
 13. A robotic device for providing verticalmobility, the robotic device comprising: a housing enclosing a vacuumchamber that is exposed to an opening on a lower surface of the housing;a flexible seal circumscribing the opening; a plurality of rod andspring strips configured to apply a downward force to the flexible seal;a ground penetration radar unit disposed inside a central compartmentthat is within the housing, the ground penetration radar unit beingsupported by a skid that is vertically mobile, wherein the groundpenetration radar unit is supported by a skid such that the groundpenetration radar unit is vertically mobile, but not laterally mobile,within the central compartment; a vacuum motor assembly operativelyconnected to the vacuum chamber; a means for moving the robotic deviceacross a surface, the means for moving being at least one wheel or atleast one tank tread; wherein actuation of the vacuum motor assemblycreates a vacuum in the vacuum chamber that pulls the housing toward thesurface such that the means for moving is pressed against the surface.14. The robotic device as recited in claim 13, wherein the flexible sealdefines a seal perimeter and the means for moving is disposed within theseal perimeter.
 15. The robotic device as recited in claim 13, whereinthe flexible seal is wrapped within a flexible fabric pocket.
 16. Therobotic device as recited in claim 13, wherein the flexible seal iswrapped within a flexible nylon fabric pocket.